Concrete surfacing machine



June 9, 1953 c. F. YTTERBERG CONCRETE SURFACING MACHINE 3 Sheets-Sheet 1 Filed July 16, 1948 June 9, 1953 Filed July 16, 1948 c. F. YTTERBERG 2,641,169

CONCRETE SURFACING MACHINE 3 Sheets-Sheet 2 June 9, 1953 c. F. YTTERBERG CONCRETE SURFACING MACHINE 3 Sheets-Sheet 3 Filed July 16, 1948 Patented June 9, 1953 UNITED STATEEB RATE OFFICE CONCRETE SURFAOING MACHINE Application July 16, 1948, Serial No. 39,001

l 2 Claims. In Patent 2,386,843, granted October 16, 1945, to Raymond E. Davis, there is disclosed a concrete surfacing machine which includes a rotary work engaging disc and mechanism for effecting rotation of that disc about a vertical axis and at the same time causing to vibrate at high frequency. It has been found to be highly advantageous to utilize a machine of this character in the surfacing of concrete slabs of stiff consistency, containing but little water, the surface being greatly improved when subjected to the action of a plate which is rotating and vibrating simultaneously.

I'he present invention has for its object the provision of a concrete surfacing machine of the ty e just above generally described, and disclosed in the Davis patent mentioned, which however has a number of improved features of construction, the purpose being to provide a machine which will operate efiiciently under all conditions of use and one which will be well to withstand the shock due to handling and inanipulation and the very considerable amount of strain to which it must necessarily be subjected when in use due to the nature of the Work which it performs.

The machine includes separate aligned eccentric members mounted on the work engagin disc and separate motors for driving said eccentrics. A novel and improved connection between the eccentrics is provided, however, whereby the eccentrics are constrained to rotate about their axes at the same angular velocity so as not to get out of phase with each other. The eccentric act-uating motors are positioned supported, and housed. in an improved manner, being secured to the undersurface of a drive plate disposed above and in parallel relationship with the work engaging disc. The drive plate in turn supports the rotor of a driving motor, the casing of the motor being adapted. to be restrained against rotation. The casing of the driving motor supports a series of contact rings and upon the drive plate is mounted a series of brushes, each brush engaging one of the contact rings, this arrangement being such that current to actuate the eccentric driving motors will at all times be available despite the fact that the drive plate will be in constant rotation when the apparatus is in use. Numerous other novel features are embodied the improved machine, as will be hereinafter pointed out. One embodiment of the apparatus is illustrated in the accompanying drawings, in which,

Figure l is a side elevation of the machine in its entirety;

Figure 2 is likewise a side elevation of the machine, as seen from a different point of view.

Figure 3 is a section on line 3-4 of Figure 2;

Figure 4 is a section on line tl of Figure 2, portion of the drive plate being broken away;

Figure 5 is a perspective view of the drive plate of the machine;

Figure 6 is a perspective view of a portion of the driven plate;

ure 3;

Figure ll is a section on line li-il of Figure 3; and

Figure 12 is a section on line iii-4i of "figure 3.

The driven or work engaging plate of the 1na-- chine comprises a circular clisc which is indicated at It in the drawings, the periphery of which is beveled as shown, so that it may be freely moved laterally over the surface of a concrete body. Preferably this plate is reinforced by means of a second or backing plate I i of annular form, attached to the upper surface oi: the work plate it by welding or other suitable means. Disposed above and parallel to the work. plate H3 is the drive plate iii, which is generally octagonal. as shown in Figure Disposed above the drive plate l2, with the axis of its rotor extend ing vertically, is a driving motor M, and to the casing 53 of this motor is connecsed the handle H by means of which the machine may be moved or manipulated when in use and which likewise serves, when gripped by an operator, a means for preventing rotation of the motor casing The details of the handle may be varied as desired but it preferably comprises a frame it the lower end of which is pivotally connected by means of aligned bolts 15 to the motor casing E3, the upper end of the handle portion l5 being connected by an adjustable link or brace ll to a bracket it securely mounted upon the upper end of the motor casing. A hand grip I9 is aflixed to the upper end of the handle and conveniently disposed adjacent the hand grip is a switch box 20 having a switch operating member 2|. It will be understood that electric current for the energization of the motor M, and also for the energization of two smaller motors to be hereinafter described, will be conducted to the apparatus from a suitable source by flexible conduits and that the flow of current to the drive and other motors will be controlled by the switch 20.

Extending downwardly from the drive plate F2 are a plurality of tubular elements 22 each of which houses and comprises a supporting base for a rod 23 the lower portion of which projects downwardly from tube 22 and is provided with a head 23a. All that portion of rod 23 which projects downwardly from its sleevelike base or support 22 is embedded in a cylindrical rubber member 24 which is firmly mounted upon a conical sleeve 25, the upper end of this sleeve being inturned and being received within an annular groove formed in member 24. The base of each sleeve 25 is mounted upon and rigidlysecured to spaced pedestals 2B which are in turn welded to reinforcing plate H. The drive plate is thus supported upon the work plate it by means which permits the work member to vibrate independently of the drive plate while at the same time this means connects the drive and work plates in such manner that the rotary motion of the drive plate is at all times communicated to the work plate.

Mounted upon the upper surface of the work plate H) are four pedestals 23, 29, 30 and 3 I, each pedestal extending through an aperture in the superposed reinforcing plate H and being welded in position. Each pedestal thus described is provided with a circular recess for the reception of a ball or roller bearing, these bearings being indicated at 33, 34, 35 and 36 respectively, all being concentrically disposed about a common axis, likewise arranged in parallel planes. Two eccentric sleeves are indicated at 38 and 39, respectively, and as will be more clearly observed in Figure 11 each eccentric sleeve has reduced ends which are mounted in two of the associated ball or roller bearings previously referred to so as to be freely rotatable about a fixed axis parallel to the work surface of plate i 0. Each eccentric sleeve has a cylindrical aperture extending through it concentric with the axis of rotation of the sleeve. A. rod 30 having a smaller diameter than the cylindrical aperture extends between the aligned eccentrics 33 and 39 and through the cylindrical apertures of the eccentrics. The outer end of each eccentric is positively connected to the adjacent end of rod 45! by a key 4|, or its equivalent.

Upon the reduced neck of each eccentric, at a point remote from key 4|, there is fixed a pulley, these pulleys being indicated at 42 and 43 respectively, and each being preferably designed for the reception of a V-belt, the V-belts being indicated at 44 and 45. By means of the belts 44 and 45 the eccentrics are operatively connected to motors 46 and 41 respectively, each eccentric being thus arranged to be driven by a single motor. The motors 46 and 41 are, as shown in the drawings, disposed between the drive and work plates I2 and I and are actually suspended from the drive plate out of contact with the work plate, which is to be vibrated at high frequency, by the supporting cushions 24 of rubber or rubber-like material. By reason of the connecting rod 40, however, the eccentrics are constrained to rotate at the same angular velocity and may not become out of phase at any time.

There is bolted or otherwise suitably secured to the lower end of the casing i3 of the motor M an annular plate 50 and this plate supports three downwardly facing conductor rings 5|, 52 and 53, these rings being disposed concentrically about the axis of the shaft of motor M. The rotor of motor M is connected, preferably through reduction gearing, with a conical member 55 which seats in a conical recess formed in the central hub 55 of the drive plate l2, member 55 and hub 56 being held against relative rotation by suitable means so that the drive plate will revolve when the motor is energized. To the casing [3 of motor M there is secured a cylindrical skirtlike extension 58 which depends toward and closely approaches the upper surface of the drive plate l2 and serves to conceal and protect the contact ring supporting plate 50.

Mounted upon the drive plate I2 are six brushes, arranged in two groups of three, the brushes being indicated at 60 and being of conventional character. Each is urged upwardly by a springlil so as to cause its upper end to engage one or the other of the contact rings. One group of three brushes is connected by suitable electrical conductors (not illustrated) with one of the eccentric driving motors and the other group of brushes is electrically connected to the second eccentric driving motor. The arrangement is thus such that the motors will be supplied with current at all times when the machine is in op-- eration despite the relative movement between the casing of the motor M and the drive plate [2 and motors 46 and 41.

The motors, the brushes, eccentrics, drive plate and other parts are so disposed with reference to the vertical axis of the motor M that the weight of the machine is equally distributed about its vertical axis, thus causing all areas of the plate In to bear upon the work with uniform pressure throughout. When the apparatus is in operation the work plate, drive plate, motors 46 and 41 and eccentrics will all revolve at a relatively high speed of rotation about the vertical axis of motor M and, at the same time the machine will be moved over the surface of the concrete so as to eventually bring all areas of said surface under treatment. The apparatus is very effective in the leveling of the surface of a slab which is of dry consistency but the apparatus is not limited in its use in this respect and may be employed where the concrete to be surfaced is of more normal water content.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In a concrete surfacing machine, in combination, parallel work and drive plates, means resiliently connecting said plates for simultaneous rotation and relative movement vertically so that the work plate may vibrate independently of said drive plate, an eccentric mounted on the work plate, a motor disposed between said plates and connected to and supported by said drive plate, a flexible connection between said motor and eccentric, and means for rotating said drive plate, said last mentioned means including a motor the rotor of which is connected to said drive plate and the casing of which is to be restrained against rotation by a suitable handle connected to said casing, brushes carried by said drive plate, contact rings mounted on the casing of said last mentioned motor, and means electrically connecting the contact rings and the motor which drives the eccentric.

2. In a concrete surfacing machine, in combination, parallel work and drive plates, means resiliently connecting said plates for simultaneous rotation while permitting the work plate to -vibrate independently of the drive plate, two

aligned eccentric sleeves supported on opposite sides of the work plate for rotation about a common axis, a motor associated with each sleeve for rotating the same, means directly connecting each such motor to the associated sleeve, each of said eccentric sleeves having a cylindrical aperture therethrough concentric with its center of rotation, and a rod of smaller diameter than said aperture extending between and connected to the outer ends of each sleeve to constrain them to rotate at the same angular velocity.

CARL F. Y'I'IERBERG.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,289,247 Davis July 7, 1942 2,386,843 Davis Oct. 16, 1945 

